26 ELEMENTS OF MAMMALIAN ANATOMY. 



Preparation of a Mammal for Dissection of the Muscles, 

 Peripheral Nerves, and Viscera.- -The simplest method 

 is to anesthetize the animal as before described, remove 

 the skin, make a slit throughout the entire ventral 

 body- wall, and immerse the specimen in a jar of 5% 

 formalin. A better method is to inject into the carotid 

 artery 200 c.c. of glycerinated formalin (water 140 

 c.c., glycerin 30 c.c., formalin 30 c.c.), and half that 

 amount into the intestine and trachea. The specimen 

 may then be preserved in the thymol and vaselin cloths 

 as previously described, or put into formalin. 



Preparation of the Central Nervous System.- The 

 animal may be killed either with chloroform or ether. 

 About 200 c.c. of formal-bichromate (170 c.c. of 5% 

 potassium bichromate and 30 c.c. of formalin) are then 

 injected slowly cephalad into the carotid artery (Figs. 3, 4, 

 and 5). After skinning, the eyes should be cut out 

 and the flesh removed from the head and dorsal side 

 of the vertebral column. On a line connecting the 

 caudal borders of the orbits, cut through the skull to 

 the brain with the bone cutters and remove piece by 

 piece the roof of the skull. Next cut away the lateral 

 walls down to the base of the brain. Care must be 

 exercised in laying bare the cerebellum, and cutting 

 loose the tentorium cerebelli, the plate of bone separating 

 the cerebrum from the cerebellum. The spinal cord 

 is next laid bare dorsally, beginning with the atlas, by 

 cutting through the pedicles of the neural arches on 

 either side. With a sharp knife or a pair of scissors 

 the spinal nerves may then be cut and the cord lifted 

 from behind forward out of its bed, until the brain is 

 reached. The latter must be carefully raised while the 

 nerves at its base are cut, and the dura mater loosened. 



To further harden them the brain and cord should 

 be placed in weak formal-bichromate (5% formalin, 500 



